Many factories, such as chemical manufacturing plants and the like, have extensive systems of piping which handle corrosive or otherwise hazardous fluids. These fluids typically consist of liquids, vapors or combinations thereof which travel through the pipes under varying pressures.
In view of the hazardous nature of these fluids, the integrity of the piping systems is critical. Notwithstanding the care exhibited in assembling and maintaining these systems, leaks occasionally develop, typically in joints between two or more pipes or between pipes and other components such as flanges, couplings, valves, expansion joints, gauges and the like. In most cases it is imperative that all of the liquid or vapor which may escape through these leaks be intercepted and contained before causing damage to equipment or, more importantly, to plant employees. This need is especially critical in those cases where the piping systems are carrying toxic materials, the escape of which would present an immediate danger to the health and even the lives of plant employees.
In addition, federal and state environmental regulations, for example, the federal Clean Air Act, as well as individual corporate air quality programs, seek to control and eliminate, or at least minimize the release of harmful materials into the environment. Such releases typically occur as standard process emissions or accidental emissions from process equipment. Many of the harmful materials these programs seek to control are cancer causing agents. Others, vapor emissions in particular, are harmful to the earth's ozone layer. Both the federal Environmental Protection Agency and the Occupational Safety and Health Administration have as their objectives the promotion and regulation of practices which minimize uncontrolled vapor and liquid releases by setting program guidelines for monitoring, detecting and containing such releases.
Presently available shields do not provide adequate safeguards to control such undesirable releases. Thus, while flexible safety shields, such as those disclosed in U.S. Pat. No. 4,106,428 to Matthiessen and co-pending application Ser. No. 07/445,176, intercept a stream of liquid which may leak from a pipe joint, they do not prevent the liquid from eventually dripping or otherwise flowing from the shield. Moreover, these flexible safety shields do not contain vapors which may escape through the pipe joint.
Other available safety shields consist of separable portions formed from a semi-rigid material which assemble around a pipe joint to form an annular chamber thereabout. The members are typically assembled by snapping the two portions together to form a loose fit about the pipe joint. Thus, since this type of shield does not form a seal around the pipe it is simply unable to contain any escaping vapors and only minimally contains escaping liquids. Furthermore, the failure of the individual components to be positively and securely assembled together presents a hazardous condition. Should a significant amount of liquid accumulate in the shield, the shield may readily come apart, exposing those persons nearby to its contents. Even in those cases when the shield does not come apart under the weight of its contents, the need to remove the shield from the pipe joint in order to empty its contents exposes maintenance workers to potential harm.
In addition, a majority of the piping systems in use today include one or more valves which may be selectively opened or closed in order to control the flow of fluids therethrough. These valves are frequently prone to leakage, particularly as they become aged and no longer provide an effective seal. Notably, none of the safety shields available today are capable of accommodating a valve without interfering with its operation, while at the same time intercepting and containing any liquid or vapor which may leak therefrom.
Thus, the need exists for an improved safety shield capable of forming an airtight seal about pipe joints and about valves in order to intercept and contain any liquid or vapor which may leak from piping systems at these points. There also exists a need for a safety shield which will surround a pipe joint or a valve in a secure fashion and not readily become disengaged therefrom. Preferably, the improved safety shield will provide adequate safeguards from the release of harmful liquids and vapors in full compliance with governmental regulations. More preferably, the improved safety shield will enable any contained fluids to be readily drained therefrom without subjecting plant employees to their hazardous contents.